Record the extent of the resource by giving the number of units and an appropriate term for the type of carrier as listed under 3.3.1.3. Record the term in the singular or plural, as applicable.
⮚Current serials.
For current serials, the extent (subfield $a) is required only for tangible non-print serials. If supplied, it contains only the designation for the type of resource.
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300 ## $a CD-ROMs [use of the term in common usage]
⮚Ceased Serials.
If a serial has ceased publication or the record is continued by another due to a major change, record the number of (bibliographic) units published, when this information is available.
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When the total number of units is uncertain or unknown, omit this information. This area does not have to be completed when closing off a record if the information is unavailable or difficult to determine.
300 ## $a volumes
⮚Illustrations and other Content (300$b)
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336 ## $a still images $b sti $2 rdacontent
⮚Dimensions (300, subfield $c)
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300 ## $a volumes ; $c 21 x 34 cm folded to 8 cm
⮚Changes in the Dimensions.
If the height changes, record the lesser height followed by the greater, regardless of the chronological sequence.
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